Optically sensitized photographic silver halide emulsion



Sept. 19, 1961 H. VON RINTELEN ETAL 3,000,738

OPTICALLY SENSITIZED PHOTOGRAPHIC SILVER I-IALIDE EMULSION Filed Jan. 31. 1956 SENSITIZATION PRODUCED BY THE DYE OF EXAMPLE 1 FIG] SENSITIZATION PRODUCED BY THE DYE OF EXAMPLE 3 FIG .2

SENSITIZATION PRODUCED BY THE DYE OF EXAMPLE 7 FIG .3

SENSITIZATION PRODUCED BY THE DYE OF EXAMPLE ll INVENTORS OSKAR R/ESTER, HARALD VO/V/Q/A TELE/V ATTORNEYS United States Patent 3,000,738 OPTICA'LLY SENSITIZED. PHOTOGRAPHIC SILVER HALIDEEMULSION Harald Von Rintelen, Koln-Riehl, and. Oskar. Riester,

Leverkusen, Germany, assignnrsto Agfa Aktiengesellschaft Filed Jan. 31, 1956, Ser. No. 562,579 Claims priority, application Germany Feb." 7, 1955 '3 Claims. (Cl. 96-102) The present: inventionrelates to optically sensitized silver halide emulsions and moreespecially to silver halide emulsions which aresensitized with cyanine dyestuffs containing a 4-mercaptopyrimidine ring.

For sensitizing photographic silver halide emulsions, it is.known.to. use cyanine dyestuflz's which.contain a pyrimidine ring. However, these dyestuffs did; not. showany particularly good sensitizing properties, so thatthey have.

notiacquired'any practical importance.

Cyanine dyestuffs which. contain the. pyrida-zine ring,

even act as desensitizers. Furthermore,,trirnethine-cya= nines which are derived from quinazoline,.which-is. a.

benzopyrimidine, according to F. M.' Hamer (J. Chem. Soc., 1932, pp. 251-260.) are:inefiective photographically.

It has now been found that cyanine dyestuffs which contain one or.more.-4-mercaptopyrimidine ringssare very suitable as optical sensitizers. The dyestuffs can exist as neutrocyaninesor as basic cyanines. Suitable dyestufis of this type have the general formulae:

In-theseformulae:

R3 stands for alkyl yl; y p p i" aryl (phenyl), aralkyl (benzyl), substituted alkyl (-O,H .CH .COOH, -(CH .SO H, --CH.CH.OH)

aryl (n y x. I

A and Bfor atoms orgroups which make. ameth'yLor.- methylene' groupi reactive and ifdesiredcan be parts.

3,%ll,738 Patented. Sept; 19, 1961 used in cyanine chemistry, such as pyridine, chinoline, t-hiazole, benzothiazole naphthiazole, oxazole, benzoxazole, naphthoxazole, indole, irnidazole, which rings may be substituted by common substituents, furthermore 4,6-di-mercapto pyrimidines,

. X for an anion, for example Cl, Br, I, CH SO and others,

nfor 0, lor 2; and n for 1,3or.5.

FIGS. 1, 2, 3 andf4e achindicate the sensitivit'y'of the silver'halid'e emulsions as a1 function" of the wave length of light; In'these figures th'e' do'tted-line curves. represent the sensitivity of the optically 'unsensiti'zed emulsions and:

the" full-line curves represent the. sensitivity of the emul sionsafter'sensitizing'withthe dyes of appended'Exampl'es 1, 3, 7 and l'l'resp ectively.

For the" production ofthesecompounds, the initiallsubstance used is a 4,6-dimercaptopyrimidine. Substances suitable as reactants for neutrocya'nines are: malonic dinitrile, malonic acid esters; rhodanine; phenylmethyl pyrazolone, thiobarbituric acid, acetoacetic ester derivatives, etc.

Examples of reactants for basic cyanines are: 2- or 4- methylcycloamrnonium salts, such as Z-methyl-benzthiazole quaternary salt, Z-methyl-benzoxazole quaternary salt, quinaldinium salt, lepidinium salt.

The preparation oftlie pyrimidinering is described in the literature. It is generally effected by alkali condensation of (substituted') malonic acid esters with amidines (formamidina, acetamidine, etc. 43, 388,575), I

Another method islhealkali condensationofLmalonic ,acidfdiamide' with esters, forexampleformic acidiethyl ester (If Chem; Sc. 51,, 2214). The 4,6:dihydroxy pyrimidines obtained"=by this method can.be converted.-

(Berichte,jvol. 71,, page 87) intoth'e dichloro compound byreaction'withhalogenation agents (P01 PO'Clg), The; dichloro compound reactsebymeanseof an alcoholic KSH solution to form the 4, d dimercaptopyrimidine compound, KCl being splitiofli- This? compound can be converted into aqueous alkaline medium With, forexample, dimethyl sulphate, into the 4,6 dimethyLmercaptopyrimidine. The latter reacts with alkylation agents, suchas methyl iodide, ethyl iodide, dimethyl sulphate, p-iodopropionic acid ester, p-toluene-sulphonic acid ester, and others, to form quaternary cycloammonium salts, which can" be condensed in the melt or dissolved inasuitable solvent, with addition of an alkaline condensation agent (for example pyridine, triethylamine, etc.),. with reactive methyl or methylene groups to cyanine dyestuffs.

Cyanine dyestufls according to the invention show a particularly good sensitizing" power and in addition are distinguished by the fact that they can be washed out satisfactorily *when the photographic materials are proc-- essed, so 'that they do not permanently dye thelayers: Furthermore, the photographic materials treated" with these dyes can be stored satisfactorily, even under extreme conditions, without any -loss=of sensitivity.

EX-AMPLB'LI Preparation:0f;4,6-dimethyl mercaptopyridine A solution of 35 g, of KOH in 500 m1. of absolute alcohol is saturated with H 8 and34 g of34,6-dichloroof a-ring'system', such as CN, ester groups such as.

carboxy methyl, carboxy'ethyl, keto groups, such as.

CH.CO'-groups, rh'odanine, thiooxazolidone, thiohydantoin; thiobarbituric acid, pyrazol'onerings;

Z for partsof a heterocyclic ring'system'; as itisordinaril'y pyrimidine are; introduced while stirring. The solution which is obtained iseboiled forlhours under reflux. The dimercaptopyrimidine is precipitatedfronr the cooled solution and is liberated from KCl by washing with water.

.Yield: 30 g.

14.4 g. of the dimercapto compoundare dissolvedsinml. of dilute caustic soda solution and.19"ml. of

dimethyl sulphate are added dropwise while stirringandcooling. Theprecipitated product is'filtered with suction and can be purified by dissolvingand recrystallizingfrom.

methanol. Yieldi 14 g. M'.P'.', 119.

(J. Chem. Soc.--

7 3 The dyestufi having the following constitution:

SCH:

inn.

can be obtained in the following manner:

1.7 g. of 4,6-dimethyl mercaptopyrimidine are melted with 1 ml. of dimethyl sulphate in a water bath, the cooled melt is dissolved with 1.4 g. of thiooxazolidone in 10 cc. of alcohol and mixed with 1.5 ml. of triethylamine. The precipitated dyestuflf is dissolved and recrystallized from methanol and has a melting point of 200 C. Sensitization range: 505 mp, sensitization maximum: 462 mp.

EXAMPLE 2 The dyestutf of the following constitution:

' SCH! c-----& k. O=C =8 is prepared in a manner similar to that of Example 1. The quaternary salt is formed with diethylsulphate and condensation is eiiected with 1.6 g. of rhodaniue in alcohol with addition of 1.51 ml. of triethylamine. The dyestufi which crystallizes out can be purified by dissolving and recrystallizing from acetone. M.P. 171 C. Sensitization range: 540 mp, sensitization maximum:

- EXAMPLE. 3 The dyestutf of the following constitution:

7 sou.

JJa a is prepared in a manner similar to that of Example 1, but 2 g. of isopropylidene rhodanine are used instead of thiooxazolidone. The dyestufi which crystallizes out can be purified by dissolving and recrystallizing from methanol-acetone-M.P. 236 with decomposition. Sensitization range 655 mp, sensitization maximum: 605 m EXAMPLE 4 The dyestuff of the following constitution:

' soH:

OCIE[ Nj i... g

is obtained as follows: 7 a

1.7 g. of 4,6-dimethyl mercaptopyrimidine are melted with 1 ml. of dimethyl sulphate in a water bath. The cooled melt is dissolved with 3.5 g. of N-ethyl-Z-methyl benzthiazolium-p-toluene sulphonate in 20 ml. of alcohol and mixed with 1.5 ml. of triethylamine. The dyestufi is precipitated by adding KI. The dyestufi can be purified by dissolving and recrystallizing from methanol. M.P. 295 with recomposition. Sensitization range: 520 mp, sensitization maximum: 475 m EXAMPLE 5 The dyestufi of the following composition:

. SCH:

EXAMPLE 6 The dyestufi? of the following composition:

SCH:

is prepared in a manner similar to that of Example 5, but

2.6 g. of lepidiuium methyl sulphate are used instead of 2-methyl benzthiazolium salt. Working up takes place as in Example 5. The dyestuff is purified by dissolving and recrystallizing from ethanol-chloroform. Melting point: 283 with decomposition. Sensitization range: 580 mp; sensitization maximum: 545 mp.

The formula for the product of this example is somewhat difierent than the second generic formula given above with respect to the double bonds between the nitro- 5f) gen in one ring and the nitrogens in the other. However,

both sets of double bonds are equivalent and interchangeable and both sets can be considered correct. The same relationship is present in the formulae given above for the products of Examples 4 and 5.

EXAMPLE 7 The dyestufi of the following constitution: 1 f

SCH:

6H8 on i...

, is obtained by melting 1.9 g. of 2-methyl-4,6dimethylmercaptopyrimidine with 1 ml. of dimethyl sulphate. The

cooled melt is dissolved with 1.4 g. of thioxazolidine in 10 ml. of alcohol and mixed with 1.5 ml. of triethylamine. The precipitated dyestufi is purified by dissolving and recrystallizing from methanol. M.P. 208. Sensitization range: 505 m sensitization maximum: 452 mp.

The dycstuif'oft'he-foll'owing constitution:

SCH:

011a, ([1111 is.-obtained.hy 1.9-.-g oi 2-methyl-4, -dimethy1:mercaptopyrimidine being melted with.-1.ml. of dimethyl sulphate, the cooled melt being dissolved in 10 ml. of alcohol and mixed with 1.5 ml. of triethyl'amine. The dyestufi is precipitated with a 30% NaCl solution and purified by dissolving and recrystallizing firom methanol. M.P. 285 Sensitization range: 535 m sensitization maximum: 465 my.

EXAMPLE 9 The. dyestufi of the following constitution:

is obtained by 2 g, ofi2,i dimethyl-4,fiedirnethyl-mercaptm pyrimidinebeing melted with 1..ml. of dimethylsulphate.

Tlie cooled melt is. dissolved with 1.6; g. of. N's ethylv rhodanine in- 10ml of alcohol and the solution with 1.5 ml. of triethylamine. The dyestufi formed is caused to crystallize by adding water and is purified by dissolving and recrystallizing from methanol. M.P. 185. Sensitization range: 545 mp; sensitization maximum:

EXAMPLE 1O Rhodacyanines of these groups are also available by the usual methods. The dyestufi of the following constitution:

SCHS

is obtained by 1 g. of the dyestufi described in Example 2 being heated with 0.5 ml. of dimethyl sulphate for minutes at 120 C. The cooled melt is dissolved with 1.6 g. of 2-methyl-3-ethyl-benzthiazolium toluene sulphonate in ml. of alcohol and mixed with 0.8 ml. of triethylamine. 7 dissolving and recrystallizing from alcohol; M.P. 298. Sensitization range: 600 m sensitization maximum: 545 mu.

EXAMPLE 11 The dyestufi of the following constitution:

s-mmnmcoon Hie CO The precipitated dyestufi is purified by triethylamine.

with 0.8 m1. of triethylamine.

e is prepared by melting 3 g. of Z-methylifififlsmerca'pti? prepionic. midi-pyrimidine. 1' ml.- oftdimethyltsulfate. 'Ihemeltiadissolved:togethen with .1.4': g, of2ethio-3.-ethyl--. oxazolidone in .10. ml. ,of .alcohol and mixedwithi 3 .mhofi. The dyestuff is precipitated by adding. dilute acetic acid and recrystallized from methanol. M.P.: 211 C. Sensitization range-506 my; sensitization maximum: 452 my.

I EXAMPLE? 12 The dyestuff. of the following constitution:

EXAMPLE 13- The dyestuii of the following constitution:

IP-Ca is prepared by melting 1.7 g. of 2-methyl-4,6-dibenzylmercaptopyrimidine with 1.5 ml. of dimethylsulfate. The melt is dissolved together with 0.8 g. of N-ethylrhodanine in 10 ml. of alcohol and the solution mixed The precipitated dyestufi is recrystallized with acetone. M.P. 174 C. Sensitization range: 560 mu; sensitization maximum: 490 m EXAMPLE 14 l The dyestuif of the following constitution:

is prepared by melting 1.9 g. of 2-methyl-4,6-dimcthyl-- mercaptopyrimidine with 1 ml. of dimethyl sulfate. The cooled melt is dissolved together with 2.1 g. of l-phenyl- 3-methyl-4-isopropylidene-pyrazolone in 10 ml. of alcohol and mixed with 1.5 ml. of triethylamine. The precipitated dyestuif is purified by recrystallizing from methanol. M.P. 240 C. Sensitization range: 585 mp; sensitization maximum: 525 mp.

7 .1 l we claim is: -s {L A photographic material comprising a silver halide emulsion layer-containing as an optical sensitizer a neutrocyhnine dye eorresponding to the formula:

R stands for a member selected from the group consisting of alkyl and ara yl;

R, stands for a eel-boxy substituted alkyl;

R; and R stand for members selected from the group consisting of hydrogen, alkyl, aryl and aralkyl;

R5 and R stand for members selected from the group consisting of hydrogen, alkyl and aryl; I

A andB stand for members selected from the class con- 25 sisting of nitrile, ester and keto groups as well as groups which constitute with the carbon to which they are 1 linked a hetero-cyclic ring system selected from the group consisting of rhodanine, thio-oxazolidone, thiohydantoin, thiobarbituric acid, and pyrazolone; 30

n is a whole number between 0 and 2.

' 3. The combination of claim 1 in-whieh the sensitizer is,

gs onr-omo 00H References Cited in the file of this patent UNITED STATES/PATENTS Zeh et al Aug. 9, 1938 Ries ter Jan. 11, 1944 Brooker et a1. June 7, 1949 Vinton July 28, 1953 FOREIGN PATENTS lish ed litmen Pub. Corp, New York, 1954. 

1. A PHOTOGRAPHIC MATERIAL COMPRISING A SILVER HALIDE EMULSION LAYER CONTAINING AS AN OPTICAL SENSITIZER A NEUTROCYANINE DYE CORRESPONDING TO THE FORMULA: 